Roof ventilators



1958 I L. L. ALLDRITT ETAL 2,82

" RQOF VENTILATORS Filed Oct. 10, 1955 2 Sheets-Sheet 1 /7 .11L AL. Q

INVENTORS LAWRENCE L. ALLpR/w- 05 1. MAY ALLOR/IT' Unite This invention relates to means for ventilating buildings, and more particularly to roof ventilators having a casing adapted to be secured to a roof as an upright outlet extension of an opening through the roof and having rotatable ventilating means operatively associated with the casing and power driven to exhaust air from the building.

It is an object of our invention to provide a roof ventilator which will exclude the elements when the ventilator is in use as well as when it is not in use.

Another object of the invention is the provision of a roof ventilator in which all of the working parts are readily accessible for repair and maintenance.

- The invention also contemplates the provision of a roof ventilator in which the throat is unimpeded by fan structure, thereby to improve the aerodynamic efiiciency of the ventilator.

Still another object of our invention is the provision of a roof ventilator in which a smooth, annular flow of air will be induced.

- Finally, it is an object of our invention to provide a roof ventilator that is economical to manufacture, easily installed, operated and repaired, efficient in operation, and rugged and durable in use.

Other objects and advantages Will become apparent from the following description taken in conjunction with theaccompanying drawings, in which;

Figure 1 is a bottom view of a roof ventilator according to the invention;

Figure 2 is an elevational sectional view of the device of Figure 1, taken on the line 2-2 thereof;

Figure 3 is a view similar to Figure 1 but showing a dilferentembodiment of the invention; and

Q Figure 4 is a view similar to Figure 2, taken on the line 44 of Figure 3.

Referring now to the drawings in greater detail, we have shown in Figures 1 and 2 a roof ventilator generally indicated at 1, comprising a round casing 3 mounted with its axis vertical on a roof 5 over an opening 7 therein. Casing 3 is provided with flashing 9. whereby it is adapted to the rectangular contour of opening 7. Casing 3 may be in the form of a truncated conical sheet, as shown, or in the form of a cylindrical sheet, or otherwise rounded; and the term round is intended to comprehend all of these shapes.

An electric motor 11 is mounted coaxially and concentrically in casing 3 by means of a bracket 13 having attachment to the side walls of easing 3 and forming a cradle for the motor. Motor 11 is of course provided with electrical wires or other conduits (not shown), for appropriate connection to an electrical outlet. Motor 11 has a rotatable drive shaft 15 extending upwardly therefrom coaxially concentrically with casing 3 and motor 11.

Mounted concentrically and coaxially above casing 3,

andspaced therefrom, is a rounded, downwardly concave d 17 supported by motor 11 by means of a hood States Patent (9 "ice means of screw-threaded fasteners to permit easy assembly and disassembly of hood 17 and bracket 19. Bracket 19 is generally, mushroom shaped and comprises an aluminum casting having an interior axial passage 21 for the reception of drive shaft 15. Bracket 19, and hence hood 17, may rest on the top of motor 11 and have splined or keyed connection with drive shaft 15; but in the embodiment shown in Figure 2, drive shaft 15 and bracket 19 are secured together in unitary assembly by welding or brazing. Bracket 19 and shaft 15 may also be secured together by a screw-threaded connection having engagement in the direction of rotation of shaft 15. In any event, shaft 15, bracket 19 and hood 17 are secured together for rotation in a unitary assembly.

Spaced about and fastened to inner side walls 23 of hood 17 is a plurality of vanes 25 in the form of angle members having a base or attachment portion 27 and a blade portion 29 disposed at right angles to attachment portion 27. Each vane 25, and particularly blade portion 29 thereof, is inclined downwardly away from the direction of rotation of hood17, so that when motor 11 is in operation and hood 17 is rotating, the lower edge of each vane 25 and blade portion 29 will trail the upper edges thereof. Thus, it will be seen that as hood 17 rotates, the vanes 25 carried thereby will induce a flow of air upwardly through casing 3 and then downwardly and outwardly between hood 17 and casing 3. 7

It has been found that a smoother flow of air is induced if vanes 25 are so disposed that a portion of blade portion 29 lies above the upper marginal edge of casing 3 and a portion of blade portion 29 below the upper marginal edge of casing 3. For this purpose, vanes 25 are disposed outwardly of the upper marginal edge of easing 3; and the. inner side walls of hood 17 extend a substantial distance outward from the upper marginal edges of casing 3. In the embodiment shown, the lower marginal edges of hood 17 are disposed below the upper marginal edges of casing 3; and blade portions 29 have the general shape of a non-rectangular parallelogram. It is preferred that the lower marginal edges of hood 17 are disposed as shown, in order to exclude driving rain from casing 3. However, the desirable aerodynamic properties of the device can be maintained even if the lower marginal edges of hood 17 are on a level with or slightly above the upper marginal edges of casing 3, by changing the shape of blade portions 29 so that they nevertheless extend below the upper marginal edges of easing 3. For example, if blade portion 29 has a substantially rectangular shape, then the inclination of inner side walls 23 will assure that the lower inner corner of such a blade portion 29 will be disposed a substantial distance below the upper marginal edges of casing 3, even though all portions of attachment portion 27 be disposed above the upper marginal edges of casing 3.

In Figures 3 and 4, we have shown a modified form of our invention, which nevertheless preserves the basic operational characteristics described above. In Figures 3 and 4 is shown a roof ventilator 1' having a round casing 3' mounted upright with its axis vertical on a roof 5' over an opening 7 therethrough and having suitable flashing 9' as before. An electric motor 11 is supported concentrically and coaxially with casing 3 by a bracket 31 attached to the upper portion of casing 3' and comprising a motor supporting ring 33 mounted on three struts 35 extending upwardly and inwardly from casing 3'.

Mounted on bracket 31 is also a rounded deflector 37 through which struts 35 pass and which is attached to the struts by welding or brazing or the like. It will also be noted that motor 11' and deflector 37 might be mounted together in unitary assembly, with struts 35 terminating aerial-s07 at and supporting deflector 37. Deflector 37 is of general bowl shape and has a central, upwardly concave portion 39 in which motor 11' is situated, and an outwardly die d P rip e f n 1 tstm gatins an Qum edge .43.

before, motor 11' is provided with an upwardly extending drive shaft 15' concentric and coaxial with casing 3', and supporting in unitary assembly a rounded, downwardly concave hood 17' through the agency of a hood support bracket 19'. Bracket 19' has a rounded upper surface as before for attachment to the upper interior surface of hood 17'; but the ,lower surface of bracket 19 is fiat to enable closer positioning to motor 11 and because bracket 19 isnever in the air stream. As before, shaft 15 is received in bracket 19' in an interior axial passage 21 welded or braz ed together, but capable of other forms of attachment as described above Attached to and spaced about inner side walls 23' of hood 17' is a plurality of vanes 25' having attachment portions 27 and blade portions 29 disposed and oriented with regard to each other and with regard to the upper marginal edges of casing 3' as described above.

The shape of hood 17' is distinctivelydiifer ent from that of the embodiments of Figures 1 and 2. Hood .17 has a bulbous, more sharply curved portion 45, struck on shorter radii of curvature than less sharply gurved portion 47. Portion 45 forms a combined motorhousingand drive attachment portion; while portion fl forms a combined vane carrier and duct wall. Portions ,45 and 47 meet in a circular, horizontally disposed, outwardly opening dihedral fold 49. Fold 49 is disposed olosely adjacent outer edge 43, so that deflector 37 and portion 47 form together a substantially continuous, smoothly curved surface presented to air emerging upward from casing 3. Fold 49 and outer edge 43 should be slightly spaced from each other, since they are in relative rot ation.

In the embodiment of Figures 1 and 2, themotor isin the upward air stream and serves to start the airstream on its annularpath. Bracket 19 also serves to end, and serves as a smoothly curved deflector as well as a hood support. There is no fan mechanism in the throat defined by casing 3. V

In the embodiment of Figures 3 and 4, there is not even a motor disposed in the throat portion; and in deed, the entire throat portion is clear except for the neglible interference of struts 35. The'emerg'entair first strikes the smoothly rounded ,surfaces'of deflector 37 and then passes to the continuing curved surfaces of portion In this way, aerodynamic efiiciency is achieved. 1

Thus, it will be'obvious from the foregoing descripn a w av ach e e a of h initial y .r esl objects of our invention.

Althoughthe presentinvention has been describe din conjunction with preferred embodiments, it is tobeunderstood that modifications and variations may be resorted to without departing from the spiriLand scope of .the in- L vention, as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope of the invention and appended claims.

We claim:

1. A power driven roof ventilator comprising in combination a round casing open at its top and bottom adapted to be mounted with its axis vertical on a roof over an opening therein, an electric motor mounted on and within said casing, a drive shaft coaxial with said casing and driven by said motor and extending upwardly frorn said motor, a rounded, downwardly concave hood supported by said drive shaft for rotation coaxially of said casing, the inner side walls of said hood extending outward a substantial distance beyond the upper marginal edges of said casing, and a plurality of vanes mounted on and spaced about said inner side walls and inclined downwardly away from the direction of rotation of said hood, said vanes extending upward from the lower edgosof said hood, the lower portion of each said an; rin paced o a d y of s upp marginal edges of said casing and extending a substantial distance below s aidnpper marginal edges of said casing.

2. A power driven roof ventilator comprising in combination a round casing open at its top and bottom adapted to be rnonnted with its axis vertical on a roof over opening ,therein, an electric motor and a round d qm" mo nte i unita s b y o and coaxial wit said earr ng id d fle t being up y concave and terminating in an outwardly directed peripheral flangesaid motor being disposed in the concavity of said deflector and having an upwardly extending drive shaft coaxial withsaid-casing, arounded, downwardly concave hood supported by and having driving connection with said drive shaft for rotation axially of said casing, the inner side of said hood extending outward a substantial distance beyond the upper marginal edges of said casing, and a plurality of vanes mounted on and spaced about said inner side Walls and inclined downwardly away from the direction of rotation of said hood, said vanes extending upward from the lower edges of said hood, the lower portion of each said vane being spaced outwardly of said upper marginal edges of said casing and extending a substantial distance below said upper marginal edges of said casing.

References Cited in the file of this patent UNITED STATES PATENTS 707,842 Hawkins et a1. Aug. 26, 1902 1,416,295 Hirschman May 16, 1922 1,773,453 Flettner Aug. 19, 1930 1,889,117 Adamcikas et al Nov. 23, 1932 2,145,131 Rhines Jan. 24, 1939 2,227,852 Smith Jan. 7, 1941 2,571,513 Ammerman Oct. 16, 1951 2,655,764 Watkins Oct. 20, 1953 2,668,491 Gerlite Feb. 9, 1954 

